A conventional IC card of the above-described type is now described in detail with reference to FIGS. 1, 2 and 3.
FIG. 1 is a cross-sectional view of a conventional IC card 20, FIG. 2 is a perspective view of the conventional IC card inserted into an inlet port of an external device, and FIG. 3 is a cross-sectional view of the IC card of FIG. 1 when it is bent.
On opposing major surfaces of a substrate 13, lands 3a, 3b, . . . 3j are disposed. Each of the lands constitutes a part of the circuit of the IC card 20. Leads 2a, 2b, . . . , 2h of IC's 1a, 1b, . . . , 1h, which may be semiconductor devices for storing or processing information, are connected to the associated lands 3a, 3b, . . . , 3j by means of solder layers 4a, 4b, . . . , 4j. Thus, the IC's 1a, 1b, 1c, 1d, 1e, 1f, 1g and 1h are electrically and mechanically coupled to the respective opposing major surfaces of the substrate 13 by the leads 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i and 2h soldered to the associated lands 3 a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i and 3h by means of the solder layers 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i and 4j. The substrate 13 on which the IC's 1a, 1b, . . . , 1h are mounted is disposed in a frame 5. A connector 6 is disposed at one end of the frame 5 for connecting the IC card 20 to an external device which is described later. The connector 6 is connected to the substrate 13 within the frame 5. A top panel 7 and a bottom panel 8 are bonded with respective adhesive layers 9a and 9b to the peripheral edges of the frame 5 on the opposite sides of the frame 5 to thereby form a casing, in which the substrate 13 with the IC's 1a-1h mounted thereon is housed. The IC's 1a, 1b, . . . 1h are bonded to the panels 7 and 8 with the adhesive layers 9a and 9b, respectively. The IC card 20 is inserted, by a user, into an external device 10 through an inlet port 10a thereof, as shown in FIG. 2, The insertion of the IC card 20 into the external device 10 causes the connector 6 of the IC card 20 to be connected to a connector (not shown) within the external device 10. When necessary processing has been completed, the IC card 20 is pulled out of the external device 10.
If the IC card 20 is roughly handled and receives abnormal force when, for example, it is inserted into or withdrawn from the external device 10, the IC card 20, particularly its rear part opposite to the end where the connector 6 is disposed, is bent in the direction perpendicular to the major surfaces of the card, as shown in FIG. 3. When the IC card 20 is bent in the clockwise direction as in the case shown in FIG. 3, not only the IC card 20 itself is deformed, but also the IC's 1a-1d, which are bonded to the top panel 7 via the adhesive layer 9a, are forced to move rearward due to the bending of the top panel 7. As for the IC's 1e-1h, which are bonded to the bottom panel 8 via the adhesive layer 9b, are forced to move forward toward the connector 6 of the IC card 20 due to the bending of the panel 8. When the IC's 1a-1d on the top surface of the substrate 13 move rearward and the IC's 1e-1h on the opposite surface of the substrate 13 move forward, force is exerted via the leads 2a-2h of the respective IC's to the associated solder layers 4a-4j. Since the amount of displacement of the rearmost IC's 1a and le is largest, the leads 2a and 2e of the IC's 1a and le are deformed more than the other leads. Accordingly, if the IC card 20 is repeatedly bent as it is inserted into the external device 10, the solder layers connected to the leads of the IC's, particularly the solder layers 4a, 4b, 4f and 4g to which the leads 2a and 2e of the IC's 1a and 1b located in the rear portion of the IC card 20 are connected, may be cracked, which may cause disconnection of the leads 2a and 2e from the associated lands 3a, 3b, 3f and 3g, or, sometimes the leads 2a and 2b may snap.
An object of the present invention is to provide an improved IC card, in which at least those IC's which are located in the rear portion of the card are not bonded to the adhesive layers so that the IC's may not be forced to move forward or rearward by the bending of the top and bottom panels which occurs when the IC card is bent as shown in FIG. 3, for example, whereby no stress is applied to the leads or the solder layers.